A statement of equality of two algebraic expressions in or more variables is called a linear equation. These are equations with just a plain old variable like "x", rather than something more complicated like x_{2} or x/y or square roots or such.

**question **1.**Solve x + 6 = –3**

**Solution: **Here, we want to get the x by itself; that is, we want to get "x" on one side of the "equals" sign, and some number on the other side. Since we want just x on the one side, this means that we don't like the "plus six" that's currently on the same side as the x. Since the 6 is added to the x, we need to get rid of it. That is, I will need to subtract a 6 from the x in order to "undo" having added a 6 to it.

Whatever you do to an equation, do the SAME thing to BOTH sides of that equation!